05-31-2008
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Join Date: May 2008
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linux-gate - x86 - a few questions
I'm aware of the linux-gate VDSO used to implement the sysenter mechanism for system calls. On older kernels this was mapped to a static location in the address space of each process. Newer kernels allow this to be dynamically located (though I don't think it's used by any distribution yet).
How do you detect, at runtime, where this is located so I can make system calls from assembly language? There's some mention of the ELF auxiliary vector but I have no idea how to access this.
Also AFAIK the sysenter instruction does not exist on AMD processors. Do AMD processors still use the linux-gate mechanism?
Does a statically linked application still have access to the linux-gate? ldd gives me 'not a dynamic executable'.
